1. Field
Example embodiments relate to a semiconductor device, and more particularly, to a semiconductor device including a two-dimensional material layer that has a two-dimensional crystal structure and is interposed between a metal and a semiconductor to reduce a contact resistivity therebetween.
2. Description of the Related Art
A semiconductor device includes a metal and a semiconductor that are in contact with each other in a particular part of the semiconductor device to externally exchange electric signals. The metal has a lower resistivity than the semiconductor and can be more easily wired to the external environment. In this case, however, a contact resistivity is generated due to a hetero-contact between the semiconductor and metal.
To reduce such contact resistivity, various methods to reduce a Schottky energy barrier between a semiconductor and a metal have been suggested. For example, a metal having a work function of about 4 eV is used for an n-type semiconductor and a metal having a work function of about 5 eV is used for a p-type semiconductor. However, because a phenomenon occurs when a work function of a metal is pinned on a surface of a semiconductor, there is a limit in reducing the Schottky energy barrier regardless of a type of the metal. As another method, a depletion width may be reduced by doping a surface of a semiconductor contacting a metal to have a relatively high concentration. However, although a doping concentration needs to be further increased as a demand for a semiconductor device having a smaller size has gradually increased, there is a limit in methods of increasing a doping concentration, maintaining a stable doping state, and reducing a depletion width according to an increase in the doping concentration.